Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions

Article abstract of DOI:10.1039/d1ra02634h

We have designed a functionalized metal-organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-NH₂) was modified with a biguanidine moiety following a covalent post-functionalization approach. The morphological and physicochemical features of the material were determined using analytical methods such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald-Hartwig C-N and Ullmann type C-O cross coupling reactions with excellent yields. A library of biaryl amine and biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or change in its activity.

Full text of DOI:10.1039/d1ra02634h

RSC Advances
View Article Online
View Journal | View Issue
PAPER
Copper nanoparticle anchored biguanidine-
modified Zr-UiO-66 MOFs: a competent
heterogeneous and reusable nanocatalyst in
Buchwald–Hartwig and Ullmann type coupling
reactions†
Cite this: RSC Adv., 2021, 11, 22278
a
*
Hojat Veisi,
Narges Neyestani,a Mozhgan Pirhayati,b Sheida Ahany Kamangar,a
Shahram Lotfi,a Taiebeh Tamoradi
and Bikash Karmakar
c
d
*
*
We have designed a functionalized metal–organic framework (MOF) of UiO topology as a support, with an
extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure
and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-
NH2) was modified with a biguanidine moiety following a covalent post-functionalization approach. The
morphological and physicochemical features of the material were determined using analytical methods
such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified
the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-
biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald–Hartwig
C–N and Ullmann type C–O cross coupling reactions with excellent yields. A library of biaryl amine and
biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the
catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or
change in its activity.
Received 3rd April 2021
Accepted 18th June 2021
DOI: 10.1039/d1ra02634h
rsc.li/rsc-advances
in view of easy handling, thermal stability, facile isolation and
reusability.12 Still, there remain problems like non-uniform
1. Introduction
distribution of catalysts and difficulty in characterizing such
entities.13 This has prompted us to design functionalized metal–
organic frameworks (MOFs) and subsequently anchor appro-
priate active sites into it. In the last few years MOFs have been
come out as a signicant group of porous materials having huge
surface areas, high degree of tunability in terms of shape and
dimensions of pore channels and pore sizes, dened and
diverse crystal structures, uniformly distributed active sites in
the whole network, adjustable active metal concentration and
possess high compatibility in chemical functionalizations
towards the secondary active metal chelations.14–16 Due to such
unique features, different engineered MOFs nd potential
applications in separation, drug delivery, magnetism, gas
storage, adsorption, water treatment, health-care applications,
chemical sensing, non-linear optics, and as a nano reactor in
catalysis.17–20 In this context, we wish to introduce a novel MOF
based heterogeneous catalytic system, the Cu adorned bigua-
nidine functionalized UiO-66-NH2 (UiO-66-biguanidine/Cu).
The core skeleton is being synthesized with [Zr6O4(OH)4] octa-
hedral secondary building units (SBU) and 2-amino-1,4-benzene
dicarboxylate (BDC) ligands where each Zr6 cluster is three
dimensionally coordinated to 12 BDC units forming a hierar-
chical framework.21–24 The biguanidine functionality, which is
The transition metals (TMs) possess great affinity to form
a broad range of complexes with various organic ligands based
on their incompletely lled atomic orbitals. There are many
reports of transition metal complexes in chelation with
synthetically designed and suitably oriented novel organic
ligands, which have otherwise numerous applications as
homogeneous catalysts in different organic transformations.1–5
However, the catalyst isolation and reusability have been the
major issue that restricts their use in view of eco-sustainability.
Thereby, heterogenization of the TM complexes by immobili-
zation over different solid supports like silica,6 magnetic
nanoparticles,7 carbon nanotubes,8 mesoporous silica,9
zeolites10 and layered materials11 has been extensively explored
aDepartment of Chemistry, Payame Noor University (PNU), Tehran, Iran. E-mail:
hojatveisi@yahoo.com
bDepartment of Applied Chemistry, Faculty of Science, Malayer University, Malayer,
Iran
cChemistry Department, Production Technology Research Institute-ACECR, Ahvaz,
Iran. E-mail: t.tabss@yahoo.com
dDepartment of Chemistry, Gobardanga Hindu College, 24-Parganas (North), India.
E-mail: bkarmakar@ghcollege.ac.in
† Electronic supplementary information (ESI) available. See DOI:
10.1039/d1ra02634h
22278 | RSC Adv., 2021, 11, 22278–22286
© 2021 The Author(s). Published by the Royal Society of Chemistry

View Article Online
Paper
RSC Advances
Scheme 1 Schematic designing of UiO-66-biguanidine/Cu nanocomposite and its application in the C-heteroatom coupling reactions.
known to be an excellent chelating ligand, has been post- synthetic organic chemistry there are limited catalytic applica-
immobilized over it and subsequently Cu NPs have been tions of post-synthetic modied MOFs via covalent surface
anchored thereon as the active catalytic site (Scheme 1). In functionalization with homodispersed co-operative active
Fig. 1 SEM images of UiO-66-NH2 (a and b); and UiO-66-biguanidine/Cu nanocomposite (c and d).
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 22278–22286 | 22279

View Article Online
RSC Advances
Paper
sites.25–29 Being encouraged by this and also in continuation to presence of 0.8 mol% UiO-66-biguanidine/Cu catalyst at 100 ꢀC
our ongoing endeavors on the development and synthetic under N2 atmosphere for requisite times. On completion
utilizations of architectured heterogeneous nanocatalysts,30–38 (monitored by TLC), the reaction was brought to ambient
we report the catalytic application of UiO-66-biguanidine/Cu in conditions and the catalyst was separated by centrifugation.
efficient C–N and C–O heterocoupling reactions (Scheme 1). The reaction was worked up in 10 mL water and the product was
These coupled products, especially those involving heterocycles, extracted into EtOAc. The organic layer was washed with brine-
nd extensive applications as important drugs and medicines, water (10 mL), dried over Na2SO4, concentrated and nally
materials and also in biology.39–41 Earlier, a number of research puried by silica gel column chromatography.
groups have reported the C-heteroatom cross coupling reac-
tions over Cu catalysts.42–48 However, most of the protocols
involved various ligand based homogeneous catalysts or
3. Results and discussions
heterogeneous catalysts being synthesized using toxic and
strong reducing agents. The procedure devised by us using UiO-
66-biguanidine/Cu catalyst is the rst report for an efficient,
ligand free green synthesis of C-heteroatom coupled products
with outstanding yields in quick intervals, making the overall
procedure industrially and sustainably viable.
3.1 Catalyst characterization data analysis
On complete synthesis of the material following post-
functionalization, we turned our attention to evaluate its
structural and physicochemical characteristics using several
analytical techniques like FT-IR, SEM, TEM, EDX, elemental
mapping and XRD. Fig. S1† displays the comparative FT-IR
spectra of UiO-66-NH2, UiO-66-biguanidine and UiO-66-
biguanidine/Cu in order to understand the stepwise building
of the material. In the spectrum of UiO-66-NH2 (Fig. S1a†),
typical vibrations appeared at 1405 and 1571 cmꢁ1 can be
credited to the symmetric and asymmetric stretching vibrations
of carboxylate groups from BDC. The H–N–H scissoring and the
C–NH2 stretching vibrations of aromatic amines are observed at
2. Experimental
2.1 Synthesis of UiO-66-NH2
1.166 g ZrCl4 (5 mmol) was dissolved in 2 mL DMF in presence
of HCl (5 mL) under sonication for 20 min at ambient condi-
tions. A solution of 2-aminobenzene-1,4-dicarboxylic acid
(5 mmol, 0.9057 g) in DMF (30 mL) was then mixed to it and
sonicated again for 20 min. The whole mixture was warmed at
80 ꢀC for 6 h followed by heating at 100 ꢀC for 24 h. On cooling
the product was obtained as microcrystalline powder. It was
isolated by centrifugation at 4000 rpm for 20 min and then
washed thrice with DMF and EtOH (30 mL). Finally, UiO-66-NH2
was obꢀtained as yellow powder (95%) on drying under vacuum
at 100 C for 24 h.
2.2 Synthesis of UiO-66-biguanidine
A 50 mL aqueous dispersion containing 0.5 g of UiO-66-NH2 was
sonicated for 10 min and then an HCl solution (0.15 mol Lꢁ1, 50
mL) of 0.168 g dicyandiamide (2 mmol) was added to it. The
mixture was heated at 100 ꢀC for 24 h. It was cooled and worked
up with 10% NaOH solution which resulted the UiO-66-
biguanidine. The solid was collected by centrifugation at
4000 rpm for 20 min. It was washed thoroughly with 1 : 1 EtOH
and dried as before.
2.3 Synthesis of UiO-66-biguanidine/Cu
0.5 g of UiO-66-biguanidine was sonicated well in H2O (50 mL)
until a homogenous dispersion was obtained. Then an aqueous
solution of CuCl2 (50 mL, 1 mg mLꢁ1) was mixed to it as Cu
source and the mixture was triturated at 12 h. The product was
isolated by centrifuger and washed twice with 20 mL water
followed by with 20 mL ethanol. It was dried under vacuum at
60 ꢀC for 24 h. Cu content in UiO-66-biguanidine/Cu was found
as 0.31 mmol gꢁ1 by ICP-OES analysis.
2.4 UiO-66-biguanidine/Cu catalyzed C–N and C–O coupling
A mixture of N/O nucleophile (1 mmol), aryl halide (1.1 mmol)
and KOH (1.5 mmol) were taken together in 3 mL dry DMF in Fig. 2 TEM images of UiO-66-NH2.
22280 | RSC Adv., 2021, 11, 22278–22286
© 2021 The Author(s). Published by the Royal Society of Chemistry

View Article Online
Paper
RSC Advances
and UiO-66-biguanidine/Cu nanocomposite (Fig. 3). With
comparison of these images, successful formation and immo-
bilization of the copper monodispersed spherical shaped
nanoparticles with a mean diameter of 20–40 nm could be
conrmed in the Fig. 3. On close observation, stacking struc-
tural units of MOF can be observed.
The chemical constitutions of both UiO-66-NH2 and UiO-66-
biguanidine/Cu nanocomposite were established on EDX
detector equipped with SEM instrument and represented in
Fig. 4. The EDX spectrum of UiO-66-NH2 showed the peaks of
Zr, C, N and O atoms which narrate the structural components
being Zr as SBU and C, N, O signifying the BDC ligand (Fig. 4a).
Fig. 4b exhibits the EDX prole of UiO-66-biguanidine/Cu,
where it shows the Cu as element in addition to the previous
elements signifying the attachment of Cu nanoparticles to UiO-
66-biguanidine, a derivative of UiO-66-NH2.
The EDX data was further justied through X-ray atomic
mapping and demonstrated in Fig. 5. Additionally, it shows the
distribution of the constitutional elements in UiO-66-
biguanidine/Cu nanocomposite. An X-ray sectional scanning
of the surface displays the homogeneous dispersion of Zr, C, N
and Cu atoms over the surface. Obviously, Zr and C display
much higher density than other elements, as being the core
component of the motif. The uniformity of active component
denitely reasons for its excellent catalytic performances.
Fig. 3 TEM images of UiO-66-biguanidine/Cu nanocomposite.
1259 cmꢁ1 and 1658 cmꢁ1 respectively. The broad peaks at
3381 cmꢁ1 and 3503 cmꢁ1 are due to the N–H symmetric and
asymmetric stretching vibrations respectively. On reaction of
UiO-66-NH2 with dicyandiamide, it results the biguanidine/UiO-
66 moiety, which was conrmed from the disappearance of all
the free amine related peaks (1658, 3381, 3503 cmꢁ1) while all
other peaks remained unchanged (Fig. S1b†). However, no
signicant changes are observed in the spectrum of UiO-66-
biguanidine/Cu from Fig. 1b, as the characteristic bands due
to immobilization Cu on the biguanidine/Zr-MOF are very weak
to be distinguished (Fig. S1c†).
The particle size, shape and texture of UiO-66-NH2 and UiO-
66-biguanidine/Cu was explored over SEM and represented in
Fig. 1 at different magnications. Both the samples have typical
structure consisting of irregular intergrown microcrystalline
polyhedra with a mean diameter of 50 to 90 nm. In a cross-
sectional view, stacking units can be observed in Fig. 1c. No
signicant change in morphology is observed in the structure
on post-functionalization or Cu attachment over it. The parti-
cles seem to be somewhat agglomerated due to high concen-
tration during sample preparations.
Further justication of SEM investigation towards the
detailed structural inherence regarding size and morphology
Fig.
4 EDX spectra of UiO-66-NH2 (a); and Cu@bigua/UiO-66
was carried out through TEM analysis of the UiO-66-NH2 (Fig. 2) nanocomposite (b).
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 22278–22286 | 22281

View Article Online
RSC Advances
Paper
Fig. 5 Elemental mapping of UiO-66-biguanidine/Cu nanocomposite.
Table 1 Nitrogen adsorption–desorption data for UiO-66-NH2, UiO-66-biguanidine and UiO-66-biguanidine/Cu
Total pore volume
Mean pore diameter
(nm)
Entry
Samples
SBET (m2 gꢁ1
)
(cm3 gꢁ1
)
1
2
3
UiO-66-NH2
UiO-66-biguanidine
UiO-66-biguanidine/Cu
1045
923
810
0.68
0.42
0.22
0.62
0.58
0.53
The nitrogen adsorption–desorption isotherms of UiO-66- biguanidine/Cu exhibits almost similar XRD pattern as the
NH2, UiO-66-biguanidine and UiO-66-biguanidine/Cu are basic UiO-66-NH2 material, which indicates the unaltered
studied and the corresponding data are summarized in Table 1. framework even aer surface modications. There was no
It can be seen that the structures of each sample featured the signicant peak of Cu detected in the prole.
type I isotherm. The Langmuir surface area of the UiO-66-NH2
was 1045 m2 gꢁ1 with pore volume of 0.68 cm3 gꢁ1. Aer the
3.2 Catalytic applications of UiO-66-biguanidine/Cu
nanocomposite
biguanidine modication, the Langmuir surface area decreased
to 923 m2 gꢁ1, while the pore volume decreased to 0.42 cm3 gꢁ1
,
Aer the complete characterizations of the as-synthesized nal
material, we paid attention on the catalytic applications. We
inspected the performance of UiO-66-biguanidine/Cu nano-
composite in the Buchwald–Hartwig (C–N) and Ullmann (C–O)
type coupling reactions. Several iodobenzene derivatives were
coupled to various N and O nucleophiles in presence of an
additive base over our catalyst, following a simplistic clean
protocol. Aer completion, the catalyst was retrieved by
centrifuge and recycled in consecutive runs. However, prior to
general studies, optimization of the reaction conditions seemed
quite signicant and hence, a reaction between indole and
which indicates occupation of the internal channels by bigua-
nidine moieties in Zr-MOF structure.49 The Langmuir surface
area of UiO-66-biguanidine/Cu catalyst decreases to 810 m2 gꢁ1
when the copper moiety is introduced.
The crystallinity and phase structure of UiO-66-NH2 and UiO-
66-biguanidine/Cu nanocomposite were analyzed by XRD study
(Fig. 6). Evidently, both the materials are poorly crystalline in
nature. Three signicant Braggs diffraction peaks of the UiO-66-
NH2 are observed at 2q ¼ 7.32, 8.72 and 25.93ꢀ respectively,
which are in close agreement with the literature. The UiO-66-
22282 | RSC Adv., 2021, 11, 22278–22286
© 2021 The Author(s). Published by the Royal Society of Chemistry

View Article Online
Paper
RSC Advances
a base, the reaction yield gradually increases and we got the best
output over 0.8 mol% Cu loaded catalyst and KOH as base at
100 ꢀC in DMF solvent (Table 2, entry 8). A moderate yield was
obtained at lower temperatures (Table 2, entries 5 and 6). While
screening the reaction in different solvents like EtOH, DMF,
toluene, DMSO, CH2Cl2 and CH3CN, we got the best result in
DMF (Table 2, entries 1–6). As the external base was signicant
in the reaction, we also studied the inuence of various bases
like KOH, NaHCO3, Et3N, Na2CO3 and K2CO3, when the rst one
afforded the best yield while the others resulted moderate to
good yields (entries 8–14). Optimizing the reaction conditions
with N-nucleophile, the same were applied using phenol as an
O-nucleophile in the reaction which also produced 90% yield.
This justies the authenticity of the said stabilized conditions.
Additionally, we carried out the variation of catalysts with the
stabilized conditions over the probe reaction which has been
shown separately in Table 3. Different precursors and inter-
mediates of the nal catalyst were involved in the catalysis in
Fig. 6 XRD patterns of UiO-66-NH2 (a); and UiO-66-biguanidine/Cu
nanocomposite (b).
Table 3 Variation of catalysts in the cross coupling of indole with
iodobenzenea
Entry
Catalyst
Time (h)
Yieldb (%)
iodobenzene was selected as a model and an array of screening
experiments were conducted applying diverse conditions like
catalyst load, solvent, base and temperature. The outcomes are
shown in Table 2. In the absence of catalyst, there was abso-
lutely no product at all and a poor yield was obtained in the lack
of external base, which signies their importance in the reac-
tion (Table 2, entries 10 and 11). In presence of catalyst and
1
2
3
4
UiO-66
UiO-66-biguanidine
UiO-66-Cu
24
24
10
10
0
0
72
96
UiO-66-biguanidine/Cu
a
Reaction conditions: indole (1.0 mmol), iodobenzene (1.1 mmol),
KOH (1.5 mmol), DMF (3.0 mL), 100 ꢀC, N2 atmosphere. b Isolated yield.
Table 2 Optimization of reaction condition for UiO-66-biguanidine/Cu catalyzed cross coupling of indole/phenol with iodobenzenea
Entry
NuH
Cat. (mol%)
Base
Solvent
T (ꢀC)
t (h)
Yieldb (%)
1
2
3
4
5
6
7
8
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Indole
Phenol
0.3
0.3
0.3
0.3
0.3
0.3
0.6
0.8
0.8
—
0.8
0.8
0.8
0.8
0.8
0.8
0.8
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
—
KOH
K2CO3
Na2CO3
Et3N
EtOH
DMF
80
10
10
10
10
24
24
10
10
24
24
12
12
10
10
10
10
10
55
75
65
65
40
50
90
96
Trace
0
75
60
85
60
75
30
90
100
100
100
60
Toluene
DMSO
CH2Cl2
CH3CN
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
70
100
100
100
100
100
100
100
100
80
9
10
11
12
13
14
15
16
17
NaHCO3
KOH
KOH
KOH
25
100
a
Reaction conditions: N/O nucleophile (1.0 mmol), iodobenzene (1.1 mmol), UiO-66-biguanidine/Cu, base (1.5 mmol), solvent (3.0 mL), N2
atmosphere. b Isolated yield.
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 22278–22286 | 22283

View Article Online
RSC Advances
Paper
order to identify and investigate the role of active site. The
reaction was absolutely failed over UiO-66 and UiO-biguanidine
as catalyst which indicates there is denitely a role of Cu in the
reaction. Now, to get a deeper insight we involved the Cu(II)
impregnated UiO-66 (UiO-66/Cu) composite in the reaction
where it afforded a moderate 72% yield. This result is very
interesting signifying the role of biguanidine, which has an
important role in stabilizing the Cu NP and also to prevent the
metal to leach. Moreover, biguanidine also protects the Cu NPs
to agglomerate.
Fig.
7
Recycling of the UiO-66-biguanidine/Cu nanocomposite
catalyst in the reaction between indole with iodobenzene.
On stabilizing the optimum conditions, the investigations
were extended in search for their generalizations through
substrate variations. A wide range of biaryl amine and biaryl
ether derivatives were synthesized by coupling of diverse aryl
iodides and aryl/heteroaryl amines or phenols under the opti-
mized conditions (Table 4). Among the N-nucleophiles (Table 4,
entries 1–15), aniline reacted much faster (4–5 h) as compared
to indole or imidazole (10–12 h) towards the N-coupled prod-
ucts, whereas, the aryl iodides were highly reactive irrespective
of their substitutions, being electron donating (CH3, OCH3) or
electron withdrawing (NO2). In most of the cases excellent yields
were obtained (>90%). Similarly, different phenols and their
derivatives were also equally compatible with various aryl
iodides resulting very good productivity (entries 16–24). All the
products are known, as given in the references, being justied
from 1H NMR data.
3.3 Reusability study of catalyst
In order to validate the catalytic sustainability and green
chemical methodology, the study of reusability is an utmost
important criterion. Aer completion of the fresh cycle of the
reaction between indole and iodobenzene, the catalyst was
recollected by centrifuger and thoroughly washed with aqueous
EtOH. It was regenerated by drying and used in the successive
runs. The UiO-66-biguanidine/Cu nanocomposite showed
signicant reactivity upto 11 successive cycles with only
a nominal change in yields. The yield was slightly decreased
aer 8th run probably due to agglomeration of catalysts. The
outcome has been displayed in Fig. 7. Also the ICP-AES analysis
of the catalyst aer 8 runs was shown that amount of Cu loaded
on the catalyst is 0.30 mmol gꢁ1, that was shown a slight change
in amount of Cu (0.31 to 0.30 mmol gꢁ1). It can be concluded
that the catalyst has good stability and the leaching of Cu from
the catalyst surface is low.
Table 4 UiO-66-biguanidine/Cu catalyzed coupling of amines and
phenols with aryl iodidesa
Entry Substrate
Aryl iodide
Time (h) Yieldb (%) Ref.c
1
2
3
4
5
6
7
8
Indole
Indole
Indole
Indole
Indole
Indole
Aniline
Aniline
Aniline
Aniline
Aniline
Aniline
Imidazole
Imidazole
Imidazole
Pyrrole
Benzimidazole
Phenol
Phenol
Phenol
Phenol
Phenol
Phenol
4-Methylphenol
4-Methoxylphenol C6H5I
2-Methylphenol C6H5I
C6H5I
p-CH3C6H4I
p-ClC6H4I
p-CH3OC6H4I 10
p-NO2C6H4I 10
o-CH3OC6H4I 12
10
10
10
96
95
95
90
92
90
96
95
90
90
95
90
88
85
70
91
86
90
90
88
92
92
75
80
92
85
50
51
50
50
50
50
52
53
53
54
52
55
53
56
57
53
53
58
59
55
55
55
60
60
60
60
4. Conclusion
C6H5I
5
4
5
5
4
5
12
12
In summary, we demonstrate a Cu nanoparticle embedded and
biguanidine modied Zr-UiO-66 MOF as a novel heterogeneous
nanocomposite catalyst. A covalent post-synthetic modication
approach was followed in this synthesis to immobilize the Cu
NPs than the conventional deposition over the MOF. The strong
chelating ability of biguanidine has been used to immobilize Cu
NPs over it. The morphological structure was evaluated through
different analytical methods. Thereaer, the nanocatalyst was
explored in the Buchwald–Hartwig C–N and Ullmann type C–O
cross coupling reactions for the synthesis of diverse range of
diaryl amine and ethers under mild and green conditions
affording outstanding yields. The material has been proved to
be sufficiently rigid to be recycled for consecutive 11 cycles with
only a slight decrease in activity aer 8 runs.
p-CH3C6H4I
p-ClC6H4I
p-CH3OC6H4I
p-NO2C6H4I
o-CH3OC6H4I
C6H5I
p-CH3C6H4I
p-CH3OC6H4I 12
C6H5I
C6H5I
C6H5I
p-CH3C6H4I
p-ClC6H4I
p-CH3OC6H4I 10
p-NO2C6H4I
o-CH3OC6H4I 12
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
10
12
10
10
10
8
C6H5I
12
12
24
Conflicts of interest
a
Reaction conditions: amines/phenols (1.0 mmol), iodobenzene (1.1
mmol), UiO-66-biguanidine/Cu (0.8 mol%), KOH (1.5 mmol), DMF
The authors declare that they have no known competing
nancial interests or personal relationships that could have
appeared to inuence the work reported in this paper.
b
(3.0 mL), stirring, nitrogen atmosphere, 100 ꢀC. Isolated yield.
c
Known product.
22284 | RSC Adv., 2021, 11, 22278–22286
© 2021 The Author(s). Published by the Royal Society of Chemistry

View Article Online
Paper
RSC Advances
26 H. Konnerth, B. M. Matsagar, S. S. Chen, M. H. G. Prechtl,
F.-K. Shieh and K. C.-W. Wu, Coord. Chem. Rev., 2020, 416,
213319.
27 L. Zhu, X.-Q. Liu, H.-L. Jiang and L.-B. Sun, Chem. Rev., 2017,
117, 8129.
Acknowledgements
We are thankful to Payame Noor University (PNU), Tehran, Iran
for nancial supports and Gobardanga Hindu College for
providing research facilities.
28 S. Koushik and S. Velmathi, Chem.–Eur. J., 2019, 25, 16451.
29 P. Li, S. Regati, H. C. Huang, H. D. Arman and B. L. Chen,
Chin. Chem. Lett., 2015, 26, 6.
30 T. Tamoradi, H. Veisi and B. Karmakar, ChemistrySelect,
2019, 4, 10953.
References
1 H. Veisi, S. Hemmati and P. Safarimehr, J. Catal., 2019, 365, 31 R. Ghorbani-Vaghei, H. Veisi, M. H. Aliani, P. Mohammadi
204.
and B. Karmakar, J. Mol. Liq., 2021, 327, 114868.
2 H. Veisi, M. Pirhayati and A. Kakanejadifard, Tetrahedron 32 H. Veisi, S. Naja and S. Hemmati, Int. J. Biol. Macromol.,
Lett., 2017, 58, 4269. 2018, 113, 186.
3 M. Kazemnejadi and A. R. Sardarian, RSC Adv., 2016, 6, 33 H. Veisi, T. Tamoradi, A. Rashtiani, S. Hemmati and
91999. B. Karmakar, J. Ind. Eng. Chem., 2020, 90, 379.
4 A. Dewaele, F. Verpoort and B. Sels, ChemCatChem, 2016, 8, 34 S. Hemmati, M. M. Heravi, B. Karmakar and H. Veisi, J. Mol.
3010.
Liq., 2020, 319, 114302.
5 H. Keypour, S. G. Saremi, H. Veisi and R. Azadbakht, RSC 35 H. Veisi, S. Azizi and P. Mohammadi, J. Cleaner Prod., 2018,
Adv., 2016, 6, 77020.
170, 1536.
6 X. Qiu, S. Han, Y. Hu, M. Gao and H. Wang, J. Mater. Chem. A, 36 H. Veisi, T. Tamoradi, B. Karmakar, P. Mohammadi and
2014, 2, 1493.
S. Hemmati, Mater. Sci. Eng., C, 2019, 104, 109919.
37 T. Tamoradi, M. Daraie, M. M. Heravi and B. Karmakar, New
J. Chem., 2020, 44, 11049.
38 H. Veisi, T. Tamoradi, B. Karmakar and S. Hemmati, J. Phys.
Chem. Solids, 2020, 138, 109256.
39 G. Evano, N. Blanchard and M. Toumi, Chem. Rev., 2008,
108, 3054.
40 J. P. Corbet and G. Mignani, Chem. Rev., 2006, 106, 2651.
7 L. Chen, B. Li and D. Liu, Catal. Lett., 2014, 144, 1053.
8 M. Navidi, B. Movassagh and S. Rayati, Appl. Organomet.
Chem., 2013, 452, 24.
9 V. Ganesan, M. Pal and M. Tiwari, Bull. Mater. Sci., 2014, 37,
623.
10 G. R. Reddy, S. Balasubramanian and K. Chennakesavulu, J.
Mater. Chem. A, 2014, 2, 15598.
11 S. Eyele-Mezui, E. Delahaye, G. Rogez and P. Rabu, Eur. J. 41 L. Luza, A. Gual and J. Dupont, ChemCatChem, 2014, 6, 702.
Inorg. Chem., 2012, 2012, 5225. 42 H. Weingarten, J. Org. Chem., 1964, 29, 3624.
12 S. Hemmati, M. Hekmati, D. Salamat, M. Youse, 43 J. C. Antilla, A. Klapars and S. L. Buchwald, J. Am. Chem. Soc.,
B. Karmakar and H. Veisi, Polyhedron, 2020, 179, 114359. 2002, 124, 11684.
13 N. C. Thacker, Z. Lin, T. Zhang, J. C. Gilhula, C. W. Abney 44 D. Toummini, A. Tlili, J. Berges, F. Ouazanni and
and W. Lin, J. Am. Chem. Soc., 2016, 138, 3501.
M. Taillefer, Chem.–Eur. J., 2014, 20, 14619.
14 A. Dhakshinamoorthy, A. M. Asiri and H. Garcia, Chem. 45 F. Monnier and M. Taillefer, Angew. Chem., Int. Ed., 2008, 47,
Commun., 2014, 50, 12800.
3096.
15 W. J. Cui, G. Y. Zhang, T. L. Hu and X. H. Bu, Coord. Chem. 46 F. Monnier and M. Taillefer, Angew. Chem., Int. Ed., 2009, 48,
Rev., 2019, 387, 79. 6954.
16 B. Gole, U. Sanyal, R. Banerjee and P. S. Mukherjee, Inorg. 47 S. Bhunia, G. G. Pawar, S. Vijay Kumar, Y. Jiang and D. Ma,
Chem., 2016, 55, 2345. Angew. Chem., Int. Ed., 2017, 56, 16136.
17 Y.-B. Huang, J. Liang, X.-S. Wang and R. Cao, Chem. Soc. Rev., 48 S. Pradhan, P. B. De and T. Punniyamurthy, J. Org. Chem.,
2017, 46, 126.
2017, 82, 4883.
18 H. C. Zhou and S. Kitagawa, Chem. Soc. Rev., 2014, 43, 5415. 49 M. Servalli, M. Ranocchiari and J. A. Van Bokhoven, Chem.
19 V. Pascanu, G. G. Miera, A. K. Inge and B. M. Matute, J. Am.
Chem. Soc., 2019, 141, 7223.
20 Q. Yang, Q. Xu and H. L. Jiang, Chem. Soc. Rev., 2017, 46,
4774.
21 V. R. Bakuru, D. Davis and S. B. Kalidindi, Dalton Trans.,
2019, 48, 8573.
22 M. Nasrabadi, M. A. Ghasemzadeh and M. R. Z. Monfared,
New J. Chem., 2019, 43, 16033.
23 H. Lv, Y. Zhang, P. Chen, J. Xue, X. Jia and J. Chen, Langmuir,
2020, 36, 4025.
24 Y.-Z. Chen and H.-L. Jiang, Chem. Mater., 2016, 28, 6698.
25 Y. Luan, H. Gao, R. S. Andriamitantsoa, N. Zheng and
G. Wang, J. Mater. Chem. A, 2015, 3, 17320.
Commun., 2012, 48, 1904–1906.
50 H. Veisi, Y. Metghalchi, M. Hekmati and S. Samadzadeh,
Appl. Organomet. Chem., 2017, 17, 3676.
51 Y. Z. Huang, J. Gao, H. Ma, H. Miao and J. Xu, Tetrahedron
Lett., 2008, 49, 948.
52 M. L. Kantam, R. Roy, S. Roy, B. Sreedhar and R. L. De, Catal.
Commun., 2008, 9, 2226.
53 N. R. Jogdand, B. B. Shingate and M. S. Shingare,
Tetrahedron Lett., 2009, 50, 4019.
54 S. Jammi, S. Sakthivel, L. Rout, T. Mukherjee, S. Mandal,
R. Mitra, P. Saha and T. Punniyamurthy, J. Org. Chem.,
2009, 74, 1971.
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 22278–22286 | 22285

View Article Online
RSC Advances
Paper
55 R. Ghorbani-Vaghei, S. Hemmati and H. Veisi, Tetrahedron 58 M. Tao and W. Lei, Tetrahedron Lett., 2007, 48, 95.
Lett., 2013, 54, 7095.
56 J. B. Zhu, L. Cheng, Y. Zhang, R. G. Xie and J. S. You, J. Org.
Chem., 2007, 72, 2737.
59 S. M. Islam, S. Mondal, P. Mondal, S. Singh Roy, K. Tuhina,
N. Salam and M. Mobarak, J. Organomet. Chem., 2012, 696,
4264.
57 M. Akhavan, S. Hemmati, M. Hekmati and H. Veisi, New J. 60 H. Veisi, M. Hamelian, S. Hemmati and A. Dalvand,
Chem., 2018, 42, 2782.
Tetrahedron Lett., 2017, 58, 4440.
22286 | RSC Adv., 2021, 11, 22278–22286
© 2021 The Author(s). Published by the Royal Society of Chemistry